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Vision-Precision Ubiquitous Indoor Localization Using...
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PD1 PD2 Microcontroller Quad OpAmp Vision-Precision Ubiquitous Indoor Localization Using Conventional Lights Chi Zhang (UW-Madison), Xinyu Zhang (UC San Diego) Indoor Localizaton Discovery Navigaton Analytcs Interacton Current Practce: Wi-Fi Inaccurate Meters of error Fragile Easily afected by dynamics Future Promise: Visible Light Positoning Accurate Robust Ubiquitous Approach ①: Camera + Photogrammetry Narrow View Low Sensitiity Energy-Hungry Long Latency Approach ②: Photodiode + Intensity Model Model is Unrealistc Obstructon Breaks model Above All: Require Extra Beacon Hardware = Huge Retrofing Cost! Departure from the Regime Angle of Arrival (AoA) Database Reusing Existng Ligh ts 0 25 50 75 86 88 90 92 94 Intensity (dB) Frequency (kHz) Localizaton Resources Chi Zhang, Xinyu Zhang, “ Pulsar: Towards Ubiquitous Visible Light Localizaton”, ACM MobiCom’17 Chi Zhang, Xinyu Zhang, “ LiTell: Robust Indoor Localizaton Using Unmodifed Light Fixtures”, ACM MobiCom’16 http://dword1511.info AoA from Photodiodes Light Irradiate angle Incident angle (AoA) θ φ r 1 2 RSS 1 = P t A t (θ) α(r) A r1 (φ) RSS 2 = P t A t (θ) α(r) A r2 (φ) RSS = P t A t (θ) α(r) A r (φ) RSS 1 A r1 (φ 1 ) RSS 2 A r2 (φ 2 ) A c (φ) = = RSS 1 RSS 2 φ = A c -1 ( ) Prototype Light CF Light CF Light CF Light CF Light CF Light AoA 3D Location Orientation Gravity & Compass Spectrum Photodiode Database Photodiode Profile Light CF Light CF Landmark Location Light CF Light CF Vector Equation 3 Lights → 3D Locaton 4 Lights → 3D Locaton + Orientaton ÷ f -1 Retrofing is costly? Reuse existng lights! Intensity is unreliable? Enable photodiode-based AoA sensing! Visible Light: No Phase! Photodiodes: No Spatal Resoluton! Need New Tricks Accuracy: 10cm / 5° Oscillaton in Driver → High Frequency Flicker Ubiquitous Stable Manufacturing Error → Diversity in Oscillators Unique “Characteristc Frequency (CF)” Turn Existng Lights into Locaton Landmarks 4X 5X 2X How to Identfy Lights without Beacons? (Phone not to Scale) Obtain AoA from 2 Diferent Photodiodes
Transcript of Vision-Precision Ubiquitous Indoor Localization Using...
PD1
PD2
MicrocontrollerQuad OpAmp
Vision-Precision Ubiquitous Indoor LocalizationUsing Conventional Lights Chi Zhang (UW-Madison), Xinyu Zhang (UC San Diego)
Indoor Localizaton
Discovery Navigaton Analytcs Interacton
Current Practce: Wi-FiInaccurate Meters of errorFragile Easily afected by dynamics
Future Promise: Visible Light PositoningAccurate Robust Ubiquitous
Approach ①: Camera + PhotogrammetryNarrow View Low SensitiityEnergy-Hungry Long Latency
Approach ②: Photodiode + Intensity ModelModel is UnrealistcObstructon Breaks model
Above All: Require Extra Beacon Hardware
= Huge Retrofing Cost!
Departure from the Regime
Angle of Arrival (AoA)
Database
Reusing Existng Lights
0
25
50
75
86 88 90 92 94
Inte
nsity
(dB)
Frequency (kHz)
Localizaton
ResourcesChi Zhang, Xinyu Zhang, “Pulsar: Towards Ubiquitous Visible Light Localizaton”, ACM MobiCom’17
Chi Zhang, Xinyu Zhang, “LiTell: Robust Indoor Localizaton Using Unmodifed Light Fixtures”, ACM MobiCom’16
http://dword1511.info
AoA from Photodiodes
Light Irradiate angle
Incident angle (AoA)θ
φ
r
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RSS1 = Pt At(θ) α(r) Ar1(φ)
RSS2 = Pt At(θ) α(r) Ar2(φ)
RSS = Pt At(θ) α(r) Ar(φ)
RSS1 Ar1(φ1)RSS2 Ar2(φ2)
Ac(φ)= =RSS1
RSS2φ = Ac
-1 ( )
Prototype
Light CFLight CFLight CF
Light CFLight CFLight AoA
3D Location Orientation
Gravity &Compass
SpectrumPhotodiode
Database
PhotodiodeProfile
Light CFLight CFLandmarkLocation
Light CFLight CFVectorEquation
3 Lights→ 3D Locaton
4 Lights→ 3D Locaton + Orientaton
÷
f -1
Retrofing is costly?Reuse existng lights!
Intensity is unreliable?Enable photodiode-based AoA sensing!
Visible Light: No Phase!Photodiodes: No Spatal Resoluton!Need New Tricks
Accuracy: 10cm / 5°
Oscillaton in Driver → High Frequency FlickerUbiquitous Stable
Manufacturing Error → Diversity in OscillatorsUnique
“Characteristc Frequency (CF)”
Turn Existng Lights into Locaton Landmarks 4X 5X 2X
How to Identfy Lights without Beacons?
(Phone not to Scale)
Obtain AoA from 2Diferent Photodiodes
